Liquid-feed system



July 9,- 1929. c. 1.. STOKES LIQUID FEED SYSTEM Filed June 12 1923 2 Sheets-Sheet INVENTOR.

Patented July 9, 1929. UNITED STATES CHARLES LAWRENCE STOKES, OF LOS ANGELES, CALIFORNIA.

LIQUID-FEED SYSTEM.

Application filed June 12, 1923. Serial No. 644,924.

My invention relates to improvements in liquid fuel systems.

The invention is particularly applicable to the liquid fuel feed system for carburetors of an internal combustion engine of an automobile wherein the liquid fuel supply is at alower level than the carburetor and at some distance therefrom.

An object of my invention is to provide an improved liquid fuel system.

Another object is to provide liquid fuel systems wherein liquid fuel may be raised from a low level tank and fed to the carburetor under all operating conditions of the carburetor.

My invention is illustrated in the accompanying drawings forming a part of this application in which;

Fig. 1 is a vertical section partly in elevation of my improved liquid feed system applied to an automobile carburetor;

Fig. 2 is a sectional view of a modification I of the liquid fuel system;

fication;

Fig. 3 is a sectional View of a further modification;

Fig. 4 is a sectional view of another modi- Fig. 5 is a sectional view of a further modification;

Fig. 6 is a sectional view of another modification;

Fig. 7 is an elevation of a modification of a part of the structure illustrated in Fig. 1; and l I Fig. 8 is a horizontal sectional view of the structure illustrated in Fig. 7.

With reference to the drawings, Fig. 1 illustrates a carburetor havingan induction passage 2 adapted to be connected to the intake manifold of an internal combustion engine for supplying a mixture of air and fuel thereto. The passage of air and fuel mixture is controlled by butterfly throttle valve 3 which is disposed in the passage 2. A venturi 4 ismounted in passage 2 and closely fits the inner walls of the passage at the upper and lower ends of the venturi but extends away from the walls at its mid portion leaving an annular space 2.

A passage 5 is provided for admitting air to the carburetor with which liquid fuel from a'nozzle 6 is commingled. The admission of air to the carburetor through passage 5 is responsive to engine suction. Fuel is supplied to nozzle 6 from a float chamber 7 conpaining a float 8 which regulates in the wellknown manner the passage of liquid fuel thereto from any source.

A passage 9 connects the induction passage 2 above the throttle 3 with the space 2 below the throttle and a pipe 12 is joined with passage 9 for subjecting a vacuum tank 16 to engine manifold and Venturi throat depression. The opposite end of pipe 12 is connected with the fuel chamber of the vacuum tank. Apassage 14 joins pipe 12 with the' float chamber 7 in order to apply the same vacuum in the float chamber as is applied to the vacuum tank.

A liquid fuel reservoir 22 constituting the main fuel supply and generally placed at a lower level than the carburetor as at the rear of the vehicle, serves as a fuel supply for the carburetor. The reservoir 22 has an air vent 23 therein so as to subject the interior of the reservoir to atmospheric pres- 25 constitute a liquid circulation loop, such as is described in my Reissue Patent N 0. 14,701. In the present instance, however, I arrange this loop for circulating liquid fuel to much greater advantage insomuch as wherein the loop of the earlier structure continued from the liquidfuel reservoir to the vacuum tank, in the present instance I dispense with the greater part of one side of the loop by returning the fuel to the upflow pipe near the tank 16.

While the operation of the structure set forth in my aforesaid patent under certain conditions is perfect, such as when used with stationary engines or in other places where the vacuum tank is not liable to be lowered below the level of the liquid fuel reservoir, the system when used upon an automobile which is passing down a steep down grade permits flooding of the carburetor. I am enabled by my present invention to entirely overcome this possibility" and at the same time to simplify and increase the efliciency of the system.

The return pipe 25 is surrounded at its upper end within tank 16, by an annular 'fuel will be such that the liquid may float 17 which serves to operate a valve 19 for opening and closing a port 20 to control the supply of liquid fuel from the reservoir 22. A small metal disc 25 surrounds valve 19 and serves to guide the valve to prevent undue fluxuations of fuel in pipe 25. A small hole 24 is formed in pipe 25 near its upper end within the tank 16 so that when the system is not in operation the liquid level in tank 16 will fall, thus opening port 20 permitting fuel to rise in pipes 18 and 25 to the level of fuel in the reservoir 22. Thus the circulating loop is ready to start when the engine is again in operation. The opening24 is sufficiently high above the bottom wall of tank 16 to maintain a small supply of liquid fuel to replenish fuel drawn from the float chamber 7, during starting of the,

engine. I

A pipe 27 on the en ine side of valve port 20 interconnects upow pipe 18 with return pipe 25 to complete the loop and the upper end of pipe 18 is slightly above the liquid level determinable b float 17 as represented at AA. Splashing of the fuel as it is delivered into tank 16 is prevented by a baflle 26 adjacent the outlet of up-flow pipe 18.

Small air vent holes 29 are provided in pipe 18 and are vertically spaced apart, one of which may be above the static fuel level therein and the other of which may be below the static level. The arrangement of the holes 29 may be best determined by experiment. Pipe 18 is surrounded by a tube 28 to a point above the upmost of the holes 29 in order to prevent splashing of liquid out through holes 29 where it may escape from the system. The purpose of the vent holes 29 is to admit air to the fuel in pipe 18 so as to reduce the specific gravity of the fuel column therein and hence assure its upward inovement to tank 16.

The valve port 20 should be placed at a level below the lowest possible fuel level of reservoir 22 in order that under extreme conditions where the reservoir is much below carburetor 7 the vacuum applied to lift the be readily brought to the lowest air hole 29, the air drawn in through holes 29 serving to lighten the rising column of liquid fuel in pipe 18, thereby permitting the same to be lifted into tank 16 responsive to the vacuum therein,.wh1le at the same time the vacuum in tank 16 is insufficient to sustain a column of liquid fuel in pipe 25 beyond a predetermined height lower than the discharge opening of pipe 25 into tank 16.

In operation my improved fuel feed system after the starting of the engine with the throttle valve 3 substantially closed, creates anextremely high vacuum 1n the induction passage 2 which acts upon the space 2 through a small hole 10 communicating and float chamber 7 is regulated by the size of a hole lltwhereby air is admitted to the space 2 and passage9 to break an exclusively high vacuum therein. The effectiveness of the hole 11 as a bleed may be reduced or increased by regulating a thumb screw 3*.

The vacuum applied to pipe 12 is trans-.

mitted to tank 16 to cause liquid fuel to be drawn from reservoir 22 through pipe 21, valve port 20, a portion of return pipe 25 interconnecting pipe 27 up through the upflow pipe 18 into the vacuum tank 16. The air admitted through openings 29 to the fuel column in pipe 18 is responsible for the elevation of the fuel to the vacuum tank. At the sametime the vacuum acting upon fuel inpipe 25 causes fuel therein to rise to a predetermined height whereby circulation is set up between pipe 18 and pipe 25 through tank 16, which action is more fully explained in my aforesaid reissuepatent.

It is apparent, therefore, that the same vacuum applied through pipe 12 to the vacuum tank 16 will also'be applied through pipe 14 to the float chamber 7, thereby liquid fuel elevated into tank 16 may runby gravity to chamber 6.-

Any fuel in the vacuum tank 16 which is above that amount required to supply the demand of the carburetor will return to the hydrostatic level of the fuel in pipe 25 and should theamount be too great, such as for instance might occur upon going down a very steep grade, the rise of the fuel level in tank 16 will cause float 17 to actuate valve 19 thereby closing off the port 20 and the supply of further fuel therethrough. When this occurs circulation will still continue through the circulation loop as described until the consumption of fuel by the carburetor causes valve port, 20 to be opened again. During the continuous circulation of fuel within the fuel circulating loop the fuel therein becomes highly charged with air and fuel vapor accumulating in the upper region of tank. 16 is drawn off into the induction passage 2 where it may become a valuable part of the fuel mixture or may be suflicient to supply all of the fuel mixture needed as at idle speed.

Upon the opening of throttle 3 the vacuum applied through aperture-10 will decrease pression between float chamber 7 and the depression at the throat of Venturi 4. The vacuum applied to the upper end of nozzle 6 is greater than that existing in space 2 because the area of the opening 11 is much less than the cross sectional area of the throat of the Venturi 4 and, therefore, the volume of air drawn in-through 2 will not appreciably effect the total volume and 'velocity of air passing into the induction passage 2 through the venturi.

A modification of the-carburetor is shown in Fig. 2 wherein the equalizing pipe 14 is replaced with a pipe 14' directly connecting the space 2 with the float chamber 7; In operation the pipe 14 functions precisely as does the pipe 14.

In Fig. 3 an assembly of the carburetor and vacuum tank 16 as a unit is shown wherein the float chamber '2' contains all of the elements as illustrated in tank 16 of Fig. 1. L i i The vacuum applied to chamber 7 is passed directly from space 2 through a pipe 14*. A restriction 14 at the point of communication between space 2 and pipe 14 serves to control the depression in pipe 14 The depression in chamber 7 a is governed by a small-air vent 14 in the top wall of the chamber.

In Fig. 4 I have illustrated a further modification wherein the Venturi tube 4 has another and smaller Venturi 4 with its delivery orifice at the throat of the venturi 4. Nozzle 6 delivers fuel to the throat of the smaller Venturi 4.

In Fig. 5 I have illustrated a modification similar to the form shown in Figs; 1 and 4 wherein control of the depression at the throat of Venturi tube 4 is controlled by joining space 2 with the interior and upper end of Venturi 4*- by a small tube 11,.

In Fig. 6 I have illustrated a modification combining the structures illustrated in Figs. 2 and 5 but in which the elements of the vacuum tank 16 are embodied in a float chamber 7 as in that form shown in Fig. 3.

At times it may be desirable to substitute in place of the up-flow tube 18 a number of small pipes 30 as shown in Figs. 7 and 8 which add, considerably to the lifting efliciency where low vacuum is produced. Such a number of pipes may be designed to supply the same volume .of fuel as the single pipe 18. Each pipe, however, would have air vent holes 29 corresponding to the holes 29 in the pipe 18 as illustrated in Fig. 1.

I find that by supplying a depression of 15 inches of gasoline to the vacuum tank 16 that I can elevate fuel from the reservoir 22 into the tank 16 when the upper end of upfiow pipe 18 is 30 inches above the liquid level in the reservoir. Thus I can make a vacuum tank of small size because I can continuously feed the carburetor, even when the vacuum is very low.

It will be noted that my loop circulating pipes 25 and 18 are at a point remote from the fuel reservoir 22,.and the loop may be supplied with fuel'by a single pipe 21 attached thereto. Under such conditions as where the vacuum tank 16 is never below the liquid level in reservoir 22, float 17 and valve 19 may be dispensed with and the system would operate successfully. The float 17 and valve 19 are merely for the purpose of accommodating the system to changes in the relative position of the apertures such as would occur when the system is used upon an automobile, motorboat or the like.

I claim 1. In a liquid feed system, the combination with a liquid fuel reservoir of a liquid fuel tank above the reservoir, means to apply a vacuum to the tank, a pipe loop connected to the tank for circulating liquid fuel nected to the tank for circulating liquid fuel therethrough, a pipe for conveying li uid fuel from the reservoir to the loop, a oat in thetank, a valve actuated by the float for cutting off said pipe from said loop and means for admitting air to the loop below said tank. V

3. In a liquid feed system, the combination with a liquid fuel reservoir of a li uid fuel tank above the reservoir, a pipe oop connected to the tank for circulating liquid fuel therethrough, a pipe for conveying liquid fuel from the reservoir to the loop, means depending on the liquid level in the tank for regulating the flow of liquid through the pipe, means to admit air to the loop below said tank and means to apply vacuum to the tank for continuously circulating liquid fuel therethrough and continuously withdrawing air and vapors of the liquid fuel therefrom.

4. The combination with an internal comtion, means to apply said vacuum to a liquid fuel tank for raising fuel thereto from the for controlling said. conduitand automate cally operatedindependently of said suction.

reservoir, means to feed liquid fuel from the tank to the carburetorand means to supply liquid fuel from the reservoir to the tank; said last mentioned means including a pipe loop connected with the tank and distant from the reservoir, a single pipe connecting the reservoir and loop and a valve for closing off said pipe when the liquid fuel in the tank reaches a predetermined level.

5. In a liquid feed system for an internal combustion engine having a carburetor for supplying liquid fuel and air to said engine, the combination of a fuel tank, a li uid fuel reservoir at a, lower level than t e tank, means to apply suction to the tank, means to feed liquid fuel from the tank to the car buretor and means to supply liquid fuel ,from the reservoir to the tank; said last mentioned means including a pipe loop connected to the tank and distant from the reservoir, the loop having an up-fiow pipe and a return pipe, a conduit connecting the reservoir and loop, and a valve placed in the loop 6, In a liquid 'eed system for internal combustion engines, each having a carburetor for supplying liquid fuel and air to the engine responsive to suction, the combination of a liquid fuel tank, a liquid fuel reservoir at a lower level than the tank, means to apply suction to the tank, means to feed liquid fuel from the tank to the carburetor and means to suppl liquid fuel from the reservoir to the tan said last mentioned means including a pipe loop connected to the tank and distant from the reservoir, the loop having an up-flow pipe and a return pipe, a conduit connecting the reservoir and loop, and a valve placed in the loop for controlling the supply offuel to said conduit depending on the liquid level in the tank and automatically operated independently of said suction.

-7. In a liquid feed system for internal combustion engines each having a carburetor for supplying liquid fuel and air to the engine responsive to suction, the combination of a liquid fuel tank, a liquid fuel reservoir at a lower level than the tank, means to apply the,en ine suction to the tank, means to feed liquid fuel from the tank to the carburetor and means to supply liquid fuel from the reservoir to the tank; said last mentioned means including a pipe loop connected to the tank and distant from the engine responsive to suction, the combination of a liquid fuel tank, a liquid fuel reservoir at a lower level than the tank, means to apply the engine suction to the tank, means to feed liquid fuel from the tank to the carburetor and means to supply liquid fuel from the reservoir to the tank; said last mentioned means including a pipe loop connected to the tank and distant from the reservoir, the loop having an up-fiow pipe and a return pipe, a conduit for passing liquid fuel from the reservoir to the loop, and a valve having a stem passing through the return pipe and means controlled by the level of the fuel in said tank for controlling the flow of liquid .fuel through the conduit.

9. In a fuel feeding system for internal combustion engines a fuel reservoir, a fuel I tank at a higher level than said reservoir, a conduit between said tank and reservoir, a conduit between saidtank and the intake of said engine for transferring fuel from said reservoir to said tank by the en 'ine suction, the upper portion of said con uit "having one or more openings in its side Wall for the introduction of air, a bypass connecting said tank with said conduit below said openings, and a float-operated valve for controlling the fiow of fuel through said conduit. 10. In afuel feeding system .for internal combustion en ines, a reservoir for liquid fuel, a liquid uel tank above the reservoir,

means for applying suction of the engine to said tank, a pipe loop connected to said tank, one ortion of said loop belng provided with small perforations for admitting-air thereto,

a conduit for conducting fuel to said loop from said reservoir, a valve anterior of said loop for controlling the flow of fuel through said conduit, and means controlled by t e height of the fuel in said tank for operating said valve. N

bigned at Wilmington, in the county of Los Angeles and State of California, this 20th day of March, A. D. 1923.

CHARLES LAWRENCE STOKES. 

